It is known for optical fibers to be connected coaxially to plug-in connectors by means of couplings. The plug-in connectors are designed with a ferrule at the free end for the purpose of central fixing. The two ferules of the plugs which are to be connected can be introduced into a sleeve of the corresponding coupling, the ferrules coming into contact at the end surfaces. The sleeve is mounted in a sleeve mount. The outer shape of the coupling housing is defined by way of the given geometries of a known installation opening. Light waves are transmitted by fiber-optic cables. In order to prevent the emission of harmful laser radiation when the plug is subjected to pulling on one side, a protective device is necessary.
A coupling with a protective device is known, for example, from EP 0 599 784 A1, there being arranged in front of the sleeve opening, as seen in the plug-in direction, a moveable protective flap which, in a closed position, at least partially overlaps the sleeve opening and, in order for the contact pin to be plugged in, can be moved into an open position, the device having an inner bushing housing which can be pushed into an outer bushing housing, and the protective flap being retained, and mounted pivotably, between the two bushing housings. The disadvantage with such a protective device is the amount of space taken up by the pivoting mechanism, with the result that it cannot be realized with small outer dimensions of the coupling. In addition, the high-outlay mechanism is cost-intensive to produce.